STANDING UP TO BULLY: An Egyptian woman tries to stop a bulldozer from trampling over a bloodied youth yesterday while protesters push a police van off a bridge. Photo: AFP/Getty Images

(AP)

Protesters push a van off a bridge. (AP)

Egypt lurched toward civil war yesterday after heavily armed riot police crushed two Cairo camps of supporters of ousted President Mohammed Morsi and ignited eight hours of brutal fighting across the world’s largest Arab country.

The Egyptian Health Ministry said 525 were killed in violence across the country, including two journalists and the 17-year-old daughter of a Muslim Brotherhood leader.

More than 200 were killed at one of the two sit-in camps of pro-Morsi protestors while more than 3700 were injured across the country.

Morsi’s Muslim Brotherhood said the “massacre” was much greater — up 2000 killed — and threatened to turn Egypt into “another Syria.”

The violence was the worst in Egypt since the 1973 Mideast war and left the Obama administration scrambling to defend its tacit endorsement of the military’s July 3 takeover.

Secretary of State John Kerry called the mayhem “deplorable” and urged the army-backed government to quickly hold elections.

But the State Department again refused to describe the ouster of the democratically elected Morsi as a “coup” — which would force a cutoff of $1.3 billion in annual aid to Cairo.

Army-backed Egyptian officials said they ordered the crackdown to stop weeks of lawless attacks on hospitals and police stations.

“We found that matters had reached a point that no self-respecting state could accept,” interim prime minister Hazem el-Beblawi said.

At dawn, Egyptian police backed by armored vehicles, bulldozers and helicopters swept through two huge encampments in Cairo that had been held by Morsi supporters for six weeks.

Witnesses reported hearing live ammunition fired for hours at the main sit-in site, near the Rabbah al-Adawiya Mosque.

Egyptians quickly exchanged grisly photos on social media, including images of protesters carrying a brain of a victim through Cairo streets. Other photos showed protesters toppling a police van from a bridge.

The Interior Ministry claimed only tear gas was used against protesters — despite eyewitness accounts of dozens of bullet-riddled bodies.